Plasticized polyvinyl acetal resin



rial tov be employed pp rs to be material, known for the purpose mentioned provided it' is mixed with a satisfactory plasticizer .These resins vary in the groups and acetate groups which they contain v withrespect to the acetal. For instance, a satis-.

. vinyl alcohol and 10% discovery Patented Mar. 2, 1943 Elmer RIDerby, Springfield, Mass., assignor, by Y OFFICE mesne assignments, to Monsanto Chemical Company, ware St. Louis, Mo., a corporation of Dela- No Drawing. Original application November 2,

1937, Serial No. 172,442.

Divided and this an- I plication January 22, 1942, Serial No. 42 7,72l

10Claims.

present invention relates to plastic mate asinterleaf material in the manufacture of safety' glass and the like. As is well, known to those skilled in the art, polyvinyl acetal resimi. e. a material made by condensing .;,an aldehyde with a partially hydrolized polyvinyl acetate such as the resin described in the patent to Morrison et al. Reissue No. 20,430, dated June an excellent if not the best but its utilization has been retarded by the dimculty which has been experienced in discovering a plasticizer which will'give to the final product the necessary properties. i

proportion of hydroxyl factory resin made with formaldehyde contains 82% acetal, 8% hydroxyl groups figured as polyacetate. Another satisfactory resin contains from to 2% acetate, 16 to 20% hydroxyl groups figured as polyvinyl alcohol and the balance acetal formed with butyraldehyde. The different resins of which the foregoing are only two examples have different properties according to the proportion of the three substituents mentioned and the particular aldehyde employed.

In a companion application Serial No. 172,443 filed Nov. 2, 1937, I have described the important that the most satisfactoryplasticizer of a given chemical series of plasticizers is that one which is most nearly incompatible with the particular resin employed and yet is miscible with it a that certain substances, particularly esters, which are not themselves. compatible with the resin in the proportions required for good quality plastic for safety glass, can be rendered compatible with polyvinyl acetal resin and will have the effect of plasticizing the resin and of producing a material which is useful for the purposes specified provided there is also present in the mixture a. suitable quantity of a second plasticizer which, in the proportion used is miscible both with the resin and the first plas- I have also discovered ticizer to produce a homogeneous plastic. It will be understood that when I refer to incompatibility of a plasticizer I realize that a very small amount of practically any plasticizer is miscible with these resins; but for safety glass a relatively large proportion'of plastioizer is required and as the amount of plasticizer is increased a point is usually reached where furtherplasticizer refuses 4 below, both plasticizers usable as plasticizers.

to mix homogeneously,'instead separating as an oily exudation or tiny droplets causing haze.

-While the second plasticizer is often miscible in all proportions with'the resin I have found quite unexpectedly that in some cases,

used alone in the proportion requiredfor good quality plastic for safety glass but a miscible mixture can be made in which the two plasticizers are so proportioned that the mixture is nearly incompatible in the amount required for good safety glass plastic. Y

As a result of this discovery I am able. to use as plasticizers certain substances which have previouslybeenrejected as plasticizers because of their incompatibility with the resin, also certain substances which have not been thought to be For instance, parts dibutyl diglycollate is incompatible withlOO parts of a polyvinyl acetal resin made with formaldehyde and containing 82% acetal, 8% hydroxyl groups figured as polyvinyl alcohol and 10% acetate, but if phenyl ethyl alcohol is added in suificient quantity, for example, 15 parts, even 50 parts of dibutyl diglycollate can be used successfully, obtaining miscibility and producing a satisfactory and useful product. For convenience, the plasticizer which is relatively incompatible with the resin may be referred to as-the noncompatible plasticizer, and the other as the solvent plasticizer. The following are other specific examples of mixtures embodying my invention:

1. Polyvinyl acetal resin made with formaldehyde and containing about 82% acetal, 8%'hydroxyl groups figured as polyvinyl alcohol and V 10% acetate, 100 parts, mixed with dibutyl phthalate 40 parts and phenyl ethyl alcohol 40 parts. Dibutyl phthalate is normally incompatible with this polyvinyl acetal resin, but is rendered so by the phenyl ethyl alcohol.

2. The same polyvinyl acetal resin 100 parts,

parts and phenyl ethyl aldiglycol dibutyrate 50 cohol 2 to 5 parts. The diglycol dibutyrate is not compatible with the acetal resin at 50 parts but 50 parts may be employed if combined with phenyl ethyl alcohol and the mixture is rendered entirely stable by the presence of 5 parts only of phenyl ethyl alcohol.

3. The same resin 100 parts, diglycol dipropionate 30 parts and butyl carbitol butyrate 30 parts. parts of butyl carbitol butyrate alone are incompatible.

4. A polyvinyl acetal resin made with butyraldehyde and'containing 0' to 2% acetate, 16 to 20% hydroxyl groups figured as alcoholand the as in Example 7 maybe immiscible if phthalate 35 parts balance acetal. This resin 100 parts dilauryl and dlethylene glycol 5 parts.

5. The same polyvinyl acetal resin 100 parts, dilauryl phthalate 40 parts and dibutyl diglycollate 20 parts. 60 parts of dilauryl phthalate are incompatible.

6. The same resin 100 parts, amyl laurate 35 parts, dibutyl phthalate 25 parts. amyl laurate alone are incompatible with this resin.

7. The same resin 100 parts, butyl laurate 35 parts, dibutyl phthalate 25 parts. v.

8. The same resin 100 parts, amyl 'laurate 60 parts, phenyl ethyl alcohol 30 parts. 60 parts of amyl laurate alone, or 60 parts oi amyl laurate plus parts of phenyl ethyl alcohol, are incompatible. I

9. The same resin 100 parts, butyl laurate 60 parts, phenyl ethyl alcohol 30 parts.

The proportions given above are those which give the most satisfactory manufacture of safety glass, due regard being had to both the cold break'test and the hot break test as judged by dropping a two pound ball at 0 F., and 120 F., respectively, on an assembly made with plastic not less than 0.015 inch nor more than 0.027 inchthick. When used in laminated glass, each of the materials produced in accordance with the foregoing examples gives substantially equal: hot and cold break .tests. The compositions mentioned give results superior to the present actate safety glass and fully comparable with the compositions mentioned in the co-pending application mentioned and based on various polyvinyl acetal resins.

The laurates' above mentioned may be pure chemical compounds or the esters of cocoanut oil fatty acids, or the esters of cocoanut oil fatty boilers have been reacids from which high moved.

35 parts of v The present application is a division of my prior application Serial Number 17?;442, flied November 2 1937.

What is claimed is: 1. A polyvinyl a'cetal resin plasticized with a mixture or phenyl ethyl alcohol and an alkyl ester of lauric acid.

2. A polyvinyl acetal resin plasticized with a mixture of phenyl ethyl alcohol and an alkyl ester of cocoanut oil fatty acids. l

3. A polyvinyl acetal resin plasticized with a mixture of phenylethyl alcohol and an alkyl ester of mum acid wherein said alkyl radical contains from four to'five carbon atoms.

4. A polyvinyl acetal resin plasticizedwith a mixture of substantially 30 parts of phenyl ethyl ;alcohol and substantially 60 parts of an alkyl final product for the ester of lauric acid for each 100 parts of resin. 5. A 'polyvinyl acetal resin 'plasticized with-a mixture of phenyl ethyl alcohol and amyl laur'at'e.

6. A polyvinyl acetal resin made with butyraldehyde and pla's't'ici'zed with a rn ixture of phenyl ethyl alcohol and amyl laurate. Y

7. A polyvinyl acetal resin made with cumaldehyde and plasticizedwith a mixture of substantially 30 parts of .phenyl ethyl alcohol and substantially parts of amyl lau'rate for each parts of resin.

8. A polyvinyl acetal resin plasticized "with "a mixture of phenyl ethyl alcohol and "butyl laurate.

9. A polyvinyl acetal resin made with bu'qyn aldehyde and plastici'zed with a mixture of phenyl'ethyl alcohol and butyl laurate.

10 A polyvinyl acetal resin made with-butyr aldehyde and plastici'ze'd with a mixture or substantially 30 parts phenyl ethyl alcohol and substantially 60 parts 'butyl -laurate for each 1'00 parts of resin. 1 p

ILMER R. DERBY. 

